WOW, just read through it all and i have to say, that's DEEP! I'd like a tank that big but i dont have the space. One day though!
Personally i'd put a load of discus fish in there, as that would make it an awesome show piece. Or put thousands of neons in there lol.
About the stand, nice colour but i thionk it would have looked better if painted white or a beige-ish colour with a dark trim. Will blend in with the garage walls and white door.
The 100g might look a bit better if it was a bit higher up, like halfway from the big tank